2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
esters, in urine we suggested a procedure involving extraction
of the analytes on microfiber, their silylation with N-tertbutyldimethylsilyl-N-methyltrifluoroacetamide
(MTBSTFA)
directly on microfiber, thermodesorption of the resulting derivatives
in a hot GC injector, GC separation, and MS detection
in the SIM mode. Three types of microfibers of various polarities
were tested: 50/30 µm DVB/Сarboxen/PDMS, 85 µm
Сarboxen/PDMS, and 70 µm Carbowax/DVB (Fig. 1.). The
best results were obtained on the first microfiber.
Unlike certain related techniques, SPME provides a
unique possibility for experimenting with various types of
microfibers differing from each other in chemical nature and
micropore size. Development of an SPME procedure always
begins with searching for an optimal microfiber. This process
is illustrated in Fig. 2.
Fig. 2. Efficiency of various microfibers for the determination
of MPA and O-AMPAs as tert-butyldimethylsilyl derivatives
In vivo animal (rats) experiments gave evidence for the
possibility of revealing exposure to OPWAs at the ≥0.5 LD 50
level within no less than 48 h after exposure. Urinary metabolites
of OPWAs could, in principle, be detected within two
weeks after exposure, but even if sufficiently high doses of
OPWAs were applied. The procedure is schematically represented
in Fig. 3 and described in detail in ref. 2 .
For retrospective establishment of exposure to OPWAs
we developed an SPME-GCMS procedure based on reactivation
of inhibited BChE (Fig. 4.). Reactivation of blood BChE
inhibited by OPWAs by the action of fluoride ion gives rise
to the parent compounds in the case of G-type agents or fluoroanhydrides
in te case of V-type agents. SPME is especially
efficient in this case, since the reactivation products are trapped
by microfiber and thus eliminated from the reaction zone,
which drives the reactivation process. Soman is best retained
by microfiber. In should be noted that the developed procedure
is feasible for the determination of total soman and for
the separate determination of reactivated and intact soman.
s451
Fig. 3. block scheme of the procedure for the determination of
O-AMPAs in urine by SPME-GCMS
Conclusions
Procedures for the determination in biomedical samples
of biomarkers of TCs have been developed. For fluoroacetic
acid, the detection limits are 0.001 mg ml –1 for drinking
and natural waters, 0.01 mg ml –1 for blood plasma, and
0.01 mg g –1 for organ homogenates (without recounting for dry
Fig. 4. block scheme of the determination of blood plasma
bChE reactivation products by SPME-GCMS
weigh). For organophosphorus warfare agents, the detection
limits in the analyzed sample volumes are 0.01 mg dm –3 for
sarin and 0.002 mg dm –3 for soman. The analysis time (including
sample preparation) is 2.5 h. Exposure to OPWAs by the
results of analysis for inhibited BChE reactivation products
can be revealed within 2 and more weeks after intoxication
with high doses.
REFEREnCES
1. Koryagina n. L., Savelieva E. I., Khlebnikova n. S.,
Goncharov n. V., Jenkins R. O., Radilov A. S.: J. Anal.
Bioanal. Chem. 386, 1395 (2006).
2. Savelieva E. I., Koryagina n. L., Khlebnikova n. S.,
Feld V. E., Radilov A. S.: Sixth International Chemical
and Biological Medical Treatment Symposium. p. 64,
Spiez, Switzerland 2006.
3. Savelieva E. I., Koryagina n. L., Radilov A. S., Khlebnikova
n. S., Feld V. E.: Fourth World Congress on
Chemical, Biological and Radiological Terrorism. p. 18,
Dubrovnik 2007.